Telephone system.



W. G. BRITTEN. TELEPHONE SYSTEM. APPLICATION FILED JULY 29.19I6.

Patented Mar. H, 1919.

2 SHEETS-SHEET1 Ga 1 9 1 I1 11 L a M d 6 m ,w a P 2 T F. F. H s s T F. F. H s 2 Q vw I and collectively 'cuit, but are adapted UNITED STATES PATENT oFEro WILLIAM G. IBBI'ITEN, 0E FANWOOD, NEW JERSEY, ASSIGNOR r0 wEs'rEmv EnEcrmc comrnmr, INCORPORATED, 0E NEW YORK,

' 'rE ErHoNE srsrnm.

To all whom it may Be it known that I, a citizen of the United States, residing at Fanwood, in the county of Union and State of New Jersey, have-invented certain new and useful Improvements in Telephone Systems, of which the following is a, full, clear, conc1se,'and exact description.

This invention relates to telephone systems, and more particularly to that class of such systems generally'known as paging or announcing systems. 7 v

Generally stated, one of the objects of this invention is the provision of a telephone system which is-very point of the number of annunciators that may be operated and the ability'to severally regulate the volume of sound produced thereby.

Anotherobject is the provision of a system of the above type in which the number of relays is very low..

A further object f this invention is the provision of means whereby it is possible to selectively operate concern;

various groups of annunflexible from the stand-- Specification or Letters Patent.

- ing WILLIAM G. B1irrrEN,

ciators and accomplish this feature without the necessity ofhaving through the In accordance with this invention, there is provided a plurality of transmitting stadevices efiectmg the selection. L

direct current pass tions, from each of which it is possible'hto' or groups of amplifiers,

mally not included to be inserted therein through the agency of selectingkeys. o prevent any irregularity in the volume of sound produced by any given receiver due to the varying of the resistance in the transcircuits of the N. Y., A. CORPORATION OF NEW YORK.

' Patented lvlar 11, 1919.

Application filed July as, 1916. Serial No. uaoao.

element. Otherfeatures will be apparent from the description hereinafter given.

The invention is illustrated in the accompanymg drawings, in which Figures land 2, taken together, diagrammatically represent an-entire system,"Fig.' 1. being a circuit diagram showing a plurality of transmitting statlons contemplated by this invention, and Fig. 2 showing the organization of the apparatus designed to be controlled by such transmitting stations.

The transmitter circuit of each of the transmitting. stations A, B and C shown in Fig. l'includes atransmitter 1, condenser2, J

the primary winding of an induction coil 3,

a non-locking key 4, arranged in the circuit as shown. The key 4, besides controls ling this transmitter circuit, also controls an energizing circuit for signals 5, one signal being located at eachtransmitting station,

which are adapted to give a busy indication at all stations when any'of the keys 4 are operated. Placed in the secondary circuit of induction coil 3 are a plurality of selecting keysfi, 7, 8, 9 and 10, preferably of the well-known locking type, which control the circuits oi? a series of compensating'resistances 11, 12, 13, 14, and 15 respectively, these resistances bemg'normally inductively "connected with the circuit of the transmitter -1 as shown. Key 4 also controls a contact piece 16, which is adapted to close the several compensating resistances when thekey is in. an actuated position.-

' to which is, led the terminals mission circuit which would result by vary- 4 ing the number of amplifiers selectively placed therein, compensating means, prefer ably located at the transmitting stations, function to regulate the strength of the energizing current for actuatingthe-amplifiers current for energizing Conductors from the transmitting stations A, B and C terminate in a panelboard, represented by the dotted lines in Figs, 1 and 2, from a suitable source of current for actuating the amplifying and other apparatus. I

' In Fig. 2 there is, shown a plurality of.- amplifiers 20, which may be similar in construction to that ter of a patent to-Henry C. Egerton, 0. 1,207,384, dated December-5, 1916. Briefly, the amplifiers 20 comprise a transmitter element oi the well-known difierential type wherein two transmitter The selecting keys are.

- illustrated in buttons are customarily used and connected with a vibrating medium in such a way that an increase in the resistance of one.button forming the subject mat- I push and pull or is accompanied by a simultaneous decrease in the resistance of the other. netsystem of the amplifiers schematically the drawing embodies a mag- I The mag netizing winding 40 wound about any i'ron 'core and arranged to magnetize the ends thereof to the same polarity. An actuating winding 41, which receives the current to be 5 amplified, is disposed soas to' operate a vibrating armature 42 which effects the operation of the transmitter-buttons 43. The transmitter elements or buttons 43 of each I amplifier20, are associated with the output circuit by beingconnected to the primary winding of an induction coil 21, the, secondary winding-of which is connected to outgolng line conductors as shown. The amplifiers are preferably arranged .in groups, the number of such groups. corresponding to the number of selecting keys located at the transmitting station. The number of amplifiers comprising the several groupsmay be varied as desired. In accordance withapproved telephone practice, there is associated with each of the. various groups ofamplifiers a protective device 22 and a high impedance coil 23, whose functions are WGll'UIIdQIStOOd-III the art. The circuit organization of the elements just desc'ri'bed is schematically represented in the .4 upper part of Fig.2. Each of the output circuits of the various amplifiers 20 may I include one ormore loud-speaking receivers 80 24 of the usual construction, which are con- -nected inmultiple when a plurality is employed. If the effective output of all of the amplifiers is substantially equal, it is possible, with the particular circuit arrangeamplifier carries tworeceivers while another carries four, the volume of. each of the two receivers .will be considerably greater than that of each of the four receivers. It will advantageous where it is desired to furnish paging service in rooms of difl'erent sizes or where, in some locations, there are apt to be disturbing noises, While otherrooms farr more 'or less quiet. j

The paging system embodying this invention will be'fullyunderstood from a descrip A, B and Omay first-selectively close the desired combinationo'f selecting keys 6 to assumed that t ted -from station A. The operation'of the key 4 efl'ects the closure of a plurality of circuits, one of which, extending from the positive side of the switch 25 located on the panel boa-rd through conductor 26,'key 4, transmitter 1,con and back to the negative side of switch 25, supplies talking current for transmitter 1. A second'circuit completed by the actuation of the key 4 effects the operation of the mentv of this invention, to vary the volume.

be apparentthat such an: arrangement is" .tion of; its operation. "A party wishing to transmit amessagefrom any of the stations 10 and then operate the key1'4. Let it be e message 1s to be'transmltuctor 27, resistance 28,

homef busy signal 5, 'the circuit fdr which extends frombatterycat oneside of switch 25, conductor 26, key 4, winding of signal 5, conductor 29, resistance 30, through the switch 25 to the other side of battery. Simultaneouslywith the completion of the circuit for the signal 5 located at transmitting station A,- a corresponding circuit is closed for the signal at station'B ,which may.

be traced from the positive side of battery at switch.25- through conductor 26, keyf4 of station A, conductors 45 and 46, winding of signal 5, conductor47 and resistancev30,

In a similar manner awcircuit is established for signal 5 located at station C. The display of thesignals 5 at the stations B and C indicate to aperson desirous of transmitting a message from one of those stations-that the'system is already in use. In addition,

the magnetizing windings 40 of all of the 'to the negative side of battery at switch 25.

amplifiers 20, are energized upon the operation of the key 4. 'The energizing circuits thus provided may be traced from the positive side of battery at'switch 25, through conductor 26, key 4, conductors 45 and 48 through all of the magnetizing windings 40' the switch 4 accomplishesthree' distinct re- ;sults which may be epitomized as follows: 4 First, current is supplled to the transmitter 1; second, the operation of all of the busy signals 5 is efl'ected'; .andthird, magnetizgoing it will be seen that theoperation of ing currentis' connected to all -of the corresponding' amplifiers 20. v I I Another circuit closed by the operation of the key 4 inductively connects the compensating resistances 11', 12;, 13, 14 and 15 in the;

transmission circuit, through-the medium of the secondary winding of the induction .coil 3; It may e mentioned herethat each of the com ensating resistances 11, 12, 13',- 14 and 15's ownat the respective transmitting stations represent approximately the total resistance of the same number of amplifiers 2 0 as controlled by a corresponding 'one ofthe selecting keys 6, 7, 8, '9 and 10, to which said resistances are connected.

For example, if selecting key 6 is operated, f y

it places in the -circuit the first three of the ampl'fiers20 which may be designated as 50', 5 and 52, which in turn operate nine of thereceivers 24 alloted to group- D. If, I

however, the selecting key 6 is in the normal Position, as shown, the ree amplifiers 50,

:51, and 52 are disconnected from the transmitting circuit and the compensating resistance 11, which represents the combined resistance of these three amplifiers, is con- .nected with the talking circuit instead. By thus keeping theresistance in the transmisweenie whether one or more of the receiver groups- D, E, F, G, H.,are being operated. Another feature that may be noted at this point-is A, B and C, the operation of one of said stations is entirely independent of the others, and when a station is not .in use, its

secondary circuit is disconnected by means of a key v 4. This arrangement avoids-the necessity of having to set the keys 6, 7, 8, 9 and 10 in a required position after announcing has been made in order not to interfere tionof the key 6 "contact 18, thereby substituting the amplifiers for operating the receivers 24 D for the compensating resistance '11. s The circuit established bythis opera-i from contact. 18 of key with the operation of the system from any other transmitting. station. from the standpoint of operation, it is immat'erialwhat position the keys 6, 7, 8, 9 and 10 of the. respective stations A, B and C occupy when not in use. r Assume, forthe sake of illustration, that the selecting key 6 is operated by the party at the transmitting station A. The opera-. opens'contact 1'1 and closes comprising group tion may be traced 6, conductorv 33, contact 34, conductor 35, secondary winding of induction coil 3, con)- ductor, 36, through the actuating windings 41 of each of-the ampl'fie'rs 50, 51, and 52,

conductor, 37, back to contact 18. The closure of this circuit places "the amplifiers 50,

' armatures' 42 51, and 52 in a condition to be agitated by voice currents. The current generated in the actuating winding of each of the amplifiers 50, 51 and 52 operates their respective hichin turn causes variations in the current passing through the primary winding ofeach of the induction coils 21 connected inthe respective circuits 0 these amplifiers. From'the secondary winding of these inductlon coils the energizing current is conveyed for'operating the loudspeaking receivers 24. It' w1ll be noted that D'the amplifier carries four of;

in g o p the receivers 24, amplifier 51 carries two,

while amplifier 52 carries three, and, as the effective output of-each of said amplifiers is preferably substantially equal, the volume of sound produced by the receivers 24 is I varied by virtue of this arrangement.

. It will be apparentv from the above dec I scriptioh that the number of receivers associated with any particular amplifier may be changed at changedconditions by increasing or decreas ing the number of. receivers associated with.

such amplifier. Such change resultsin altering the relative volume 0f sound produ the arrangement of the secondarycircuit of each of the transmitting stations Consequently, L

any time to meet existing or ced it 4. A telephone system including a trans- V 7 has been operated instead of key 6, four of the amplifiers 20 would have been placed in the transmission circuit, these amplifiers in turn actuating the loud-speaking receivers 24 forming group E. By operating'keys 8,9 and 10, groups of receivers F, and H, respectively, may be actuated. From the above it is obvious that any or all of the groups of receivers may be operated from any of the transmitting stations by the operation of the selecting keys controlling their introduction into the transmission circuit.

From the above it will be apparent that the paging system contemplated by this inventlon is characterized b its elasticity both from the standpoint o the number of loud-speaking receivers that may be operated at a given time and the possibility-of varying the respective volumes thereof. Another prominent feature is the absence of relays or equivalent electromagnetic switching devices usually found in a paging system having the flexibility of the onein question. j

While the preferred embodiment of this invention is herein shown and particularly described, it is not intended to be limited to 1-00 the precise details of the c'ircu'it organizationillustrated, as changes may readily be i made without departing from the spirit of the invention.

What is claimed is 1. 'A telephone system. including a lurality of' transmittlng stations, ampli ers, means adapted to actively. associate any station with independent predetermined groups of said amplifiers, and compensators f controlled by said means for'maintaining the output of said amplifiers substantially constant- I 2. A telephone systems including a transmitting station, amplifiers, circuits adapted to selectively associate the amplifiers with said station, compensating resistances, and means for eflectlng the interchanging of said amplifiers and said resistances in a given circuit A I 3. A telephone system including a transmitting station, amplifiers, means adapted to actively associate said station with independent p'redetermiped groups of said am-' plifiers, and compensating resistances nor- .mally in an energizing circuit for said amlifiers but arranged to be removed thereroin for maintaining the output of the amplifiers substantially constant.

said station includin I ances adapted to be associated with the sec- 5-ondary winding of-said induction coil, am-

' plifiers, and means for substituting said amcircmt.

plifirs for said resistances insaid secondary A telephone system inoluding a lu-' rality of transmitting stations, ampli ers,

loud-sgeaking receivers connected to. said amp ii ers, said-amplifiers and receivers befor directly telephon'i'cally connecting any of said; groups with said transmitting station. I In witness whereof, I hereunto subscribe my name this 28th day of July, A. D., 1916.- v

- WILLIAM G.BRIITTE\N. 

